Last week, Tiffany and Luis decided to see how fast they could sprint 100 meters. They asked their friend Stephanie to time them with a stopwatch. After 3.61 minutes, Stephanie agreed to time the runners. Tiffany sprinted first and ran 100 meters in 37.11 seconds. When it was Luis's turn, he sped off and completed the run in 21.2 seconds. How much faster was Luis than Tiffany in seconds?
Explanation: To find how much faster Luis was than Tiffany, we need to find the difference between their times in seconds. Tiffany's time - Luis's time = difference in times. ${3}$ ${7}$ ${1}$ ${1}$ ${2}$ ${1}$ ${2}$ ${0}$ ${-\vphantom{0}}$ ${1}$ ${9}$ ${5}$ ${1}$ Luis was 15.91 seconds faster than Tiffany.